We definately need to be using different groups for a P2P War. With P2P you need a lot less people to KO a target. You don't want to all be on one pile, it's a waste of time and resources.
I'd suggest splitting into a 'Sniper' group which consists of 86% rangers, 14% meleers who would be attacking mages and other vulnerable targets from the edge, led by one leader. The 14% consistency of meleers would serve as an anti-snipe for the snipers and would preferably be high levels.
A 'Melee' group consisting of 100% meleers (with rune c'bows) - These meleers would have top tanking/melee gear and also have full karils/armadyl to switch to when being maged. Also they would have a rune c'bow for when frozen so they are not idle. This group would be led by a leader, with a backup.
A 'Mage' group consisting of 74% mages and 26% meleers. The meleers would have the same gear as the meleers in the melee group. The mages would be wearing ahrims (not mystic... or they'd be ko'd..) and would be using MULTI SPELLS meaning barrage or at the lowest burst. (Keep it to barrage though imo). This group would also be led by one leader with a backup leader.
Say we pull 55 to the war. We should have:
Melee Group (25)-
-25 Meleers
Snipe Group (15)-
-13 Rangers
-2 Meleers
Mage Group (15)-
- 11 Barragers
- 4 Meleers
------------------------------------
My starting ideas for Attacking:

Key: Red = Melee group, Green = Ranger Group, Blue = Mager group
As shown, we'd try and keep the three sectors seperate from the begining, with about a 2 second delay between main melee sector running in, and the others following. The snipers and mages try to stay behined the walls doing their stuff, while meleers in the middle do their stuff. The anti snipers for the snipe/mage sector should be one on each side of the mage/range groups for protection. These should be high level people.
My starting ideas for Defending:

Key: Red = Melee group, Green = Ranger Group, Blue = Mager group, Cyan = KO group
As shown, the same setup as BTO's for the start except over a larger area so that nobody is stood on top of eachother (to make as least amount of people barraged at first as possible). Then, once they've charged the range & mage sectors run to their respective sides of the fight and do their thing, with their anti snipers in same position as last time.
Any questions? Suggestions? Errors? Disagreements? Agreements?

~Mugger84